var chessBoard = [];
var me = true;
var over = false;
//赢法数组
var wins = [];
//赢法的统计数组
var myWin = [];
var computerWin = [];

for(var i=0;i<15;i++){
    chessBoard[i] = [];
    for(var j=0;j<15;j++){
        chessBoard[i][j] = 0;
    }
}
for(var i = 0; i<15; i++){
    wins[i] = [];
    for(var j =0;j<15; j++){
        wins[i][j] = [];
    }
}
    var count = 0;
    for(var i = 0; i<15; i++){
        for(var j = 0; j<11; j++){
            for(var k = 0;k<5; k++){
                wins[i][j+k][count] = true;
            }
            count ++;
        }
    }         //直线赢法
    for(var i = 0;i<15; i++){
        for(var j = 0; j<11; j++){
            for(var k = 0;k<5; k++){
                wins[j+k][i][count] = true;
            }
            count ++;
        }
    }          //竖线赢法
    for(var i =0;i<11; i++){
        for(var j = 0; j<11; j++){
            for(var k =0; k<5;k++){
                wins[i+k][j+k][count] = true;
            }
            count ++;
        }
    }           //斜线赢法
    for(var i = 0; i<11; i++){
        for(var j = 14; j>3; j--){
            for(var k =0; k<5; k++){
                wins[i+k][j-k][count] = true;
            }
            count ++;
        }
    }         //反斜线赢法

    for(var i = 0;i<count; i++){
        myWin[i] = 0;
        computerWin[i] = 0;
    }        //初始化mywin和computerwin
var chess = document.getElementById('chess');
var context = chess.getContext('2d');


context.strokeStyle = "#BFBFBF";

var logo = new Image();
logo.src="img/appale.png";
logo.onload = function(){
    context.drawImage(logo,0,0,450,450);
    drawChessBoard();

}
var drawChessBoard =function(){
    for(var i = 0; i<15; i++){
        context.moveTo(15 + i*30,15);
        context.lineTo(15 + i*30,435);
        context.stroke();
        context.moveTo(15 , 15+i*30);
        context.lineTo(435,15 + i*30);
        context.stroke();
}
}

var oneStep = function(i,j,me){
    context.beginPath();
    context.arc(15 + i*30,15 + j*30,13,0,2 * Math.PI);
    context.closePath();
    var gradient = context.createRadialGradient(15 + i*30 +2,15 + j*30 -2,13,15 + i*30 +2,15 + j*30-2,0);
    if(me){
        gradient.addColorStop(0,"#0A0A0A");
        gradient.addColorStop(1,"#636766");
    }
    else{
        gradient.addColorStop(0,"#D1D1D1");
        gradient.addColorStop(1,"#F9F9F9");
    }
    context.fillStyle = gradient;
    context.fill();
};

chess.onclick = function(e){
    if(over){
        return;
    }
    if(!me){
        return;
    }
    var x = e.offsetX;
    var y = e.offsetY;
    var i = Math.floor(x / 30);
    var j = Math.floor(y / 30);
    if(chessBoard[i][j] == 0){
        oneStep(i,j,me);
            chessBoard[i][j] = 1;

       for(var k = 0;k<count; k++){
           if(wins[i][j][k]){
               myWin[k]++;
               computerWin[k] = 6;
               if(myWin[k] == 5 ){
                   window.alert("你赢了！");
                   over = true;
               }
           }
       }
       if(!over){
           me = !me;
           computerAI();
       }
    }
};
var computerAI = function(){
    var myScore = [];
    var computerScore = [];
    var max = 0;
    var u = 0, v = 0;
    for(var i = 0;i<15;i++){
        myScore[i] = [];
        computerScore[i] = [];
        for(var j = 0;j<15; j++){
            myScore[i][j] = 0;
            computerScore[i][j] = 0;
        }
    }
    for(var i = 0; i<15; i++){
        for(var j = 0;j<15;j++){
            if(chessBoard[i][j] == 0){
                for(var k = 0;k<count; k++){
                    if(wins[i][j][k]){
                        if(myWin[k] == 1){
                            myScore[i][j] += 200;
                        }else if(myWin[k] == 2){
                            myScore[i][j] += 400;
                        }else if(myWin[k] == 3){
                            myScore[i][j] += 2000;
                        }else if(myWin[k] == 4){
                            myScore[i][j] += 10000;
                        }
                        if(computerWin[k] == 1){
                            computerScore[i][j] += 220;
                        }else if(computerWin[k] == 2){
                            computerScore[i][j] +=420;
                        }else if(computerWin[k] == 3){
                            computerScore[i][j] += 2100;
                        }else if(computerWin[k] == 4){
                            computerScore[i][j] += 20000;
                        }
                    }
                }
                if(myScore[i][j] > max){
                    max = myScore[i][j];
                    u = i;
                    v = j;
                }  else if(myScore[i][j] == max){
                    if(computerScore[i][j] >computerScore[u][v]){
                        u = i;
                        v = j;
                    }
                }
                if(computerScore[i][j] > max){
                    max = computerScore[i][j];
                    u = i;
                    v = j;
                } else if(computerScore[i][j] == max){
                    if(myScore[i][j] > myScore[u][v]){
                        u = i;
                        v = j;
                    }
                }
            }
        }
    }
    oneStep(u,v,false);
    chessBoard[u][v] = 2;
    for(var k = 0;k<count; k++){
        if(wins[u][v][k]){
            computerWin[k]++;
            myWin[k] = 6;
            if(computerWin[k] == 5 ){
                window.alert("你输了！");
                over = true;
            }
        }
    }
    if(!over){
        me = !me;
    }
}